.TH std::deque::erase 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::deque::erase \- std::deque::erase

.SH Synopsis
   iterator erase( iterator pos );                          \fI(until C++11)\fP
   iterator erase( const_iterator pos );                    \fI(since C++11)\fP
   iterator erase( iterator first, iterator last ); \fB(1)\fP                   \fI(until C++11)\fP
   iterator erase( const_iterator first,                \fB(2)\fP               \fI(since C++11)\fP
   const_iterator last );

   Erases the specified elements from the container.

   1) Removes the element at pos.
   2) Removes the elements in the range [first, last).

   All iterators and references are invalidated, unless the erased elements are at the
   end or at the beginning of the container, in which case only the iterators and
   references to the erased elements are invalidated. The end() iterator is also
   invalidated unless the erased elements are at the beginning of the container and the
   last element is not erased.

   The iterator pos must be valid and dereferenceable. Thus the end() iterator (which
   is valid, but is not dereferenceable) cannot be used as a value for pos.

   The iterator first does not need to be dereferenceable if first == last: erasing an
   empty range is a no-op.

.SH Parameters

   pos         - iterator to the element to remove
   first, last - range of elements to remove
.SH Type requirements
   -
   T must meet the requirements of MoveAssignable.

.SH Return value

   Iterator following the last removed element.

   1) If pos refers to the last element, then the end() iterator is returned.
   2) If last == end() prior to removal, then the updated end() iterator is returned.
   If [first, last) is an empty range, then last is returned.

.SH Exceptions

   Does not throw unless an exception is thrown by the assignment operator of T.

.SH Complexity

   Linear: the number of calls to the destructor of T is the same as the number of
   elements erased, the number of calls to the assignment operator of T is no more than
   the lesser of the number of elements before the erased elements and the number of
   elements after the erased elements.

.SH Notes

   When container elements need to be erased based on a predicate, rather than
   iterating the container and calling unary erase, the iterator range overload is
   generally used with std::remove()/std::remove_if() to minimise the number of moves
   of the remaining (non-removed) elements, this is the erase-remove idiom.
   std::erase_if() replaces the erase-remove idiom.
   \fI(since C++20)\fP

.SH Example


// Run this code

 #include <deque>
 #include <iostream>


 void print_container(const std::deque<int>& c)
 {
     for (int i : c)
         std::cout << i << ' ';
     std::cout << '\\n';
 }

 int main()
 {
     std::deque<int> c{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
     print_container(c);

     c.erase(c.begin());
     print_container(c);

     c.erase(c.begin() + 2, c.begin() + 5);
     print_container(c);

     // Erase all even numbers
     for (std::deque<int>::iterator it = c.begin(); it != c.end();)
     {
         if (*it % 2 == 0)
             it = c.erase(it);
         else
             ++it;
     }
     print_container(c);
 }

.SH Output:

 0 1 2 3 4 5 6 7 8 9
 1 2 3 4 5 6 7 8 9
 1 2 6 7 8 9
 1 7 9

   Defect reports

   The following behavior-changing defect reports were applied retroactively to
   previously published C++ standards.

     DR    Applied to          Behavior as published              Correct behavior
                      first was required to be
   LWG 151 C++98      dereferenceable, which                  not required if
                      made the behavior of clearing an empty  first == last
                      deque undefined
                                                              it is invalidated if the
   LWG 638 C++98      the past-the-end iterator was not       elements are
                      invalidated                             erased from the middle or
                                                              the end

.SH See also

   erase(std::deque)    erases all elements satisfying specific criteria
   erase_if(std::deque) \fI(function template)\fP
   (C++20)
   clear                clears the contents
                        \fI(public member function)\fP
